1. Field of the Invention
The present invention relates generally to a semiconductor device, and more particularly to a method for forming a silicon on insulator structured substrate with body-contacts under the gate conductor.
2. Description of Related Art
In the silicon on insulator ("SOI") art, it is well recognized that the resistance-capacitance ("RC") delay associated with body-contacts to wide channel MOSFETS limits the effectiveness of body-charge equilibrium at high-speeds. This occurs because the charge associated with the SOI body must traverse the half-width of the MOSFET. The resistance of the path increases with increasing width of the main channel until RC time constant of the body contact becomes a significant factor, which may cause unstable device behavior. The increased resistance degrades the ability of the device to remove hole charge (majority carriers in an NMOSFET) because in a wide channel device the holes leaving the body must traverse a long path. An analogous situation exists in SOI PMOSFETS, where excess electrons in the body comprise the majority carrier charge to be removed. Excess holes remain in the body of the device causing the device to latch up and lose gate control. With the need for wide devices in the semiconductor art, it is difficult to achieve a stable device.
Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a method and structure for efficient body-contact operation for SOI MOSFETS of any width operating at high-speeds.
It is another object of the present invention to provide a method and structure for SOI body-contacts that are easily integrated into existing SOI processes.
It is another object of the present invention to enhance the ability of a wide body SOI MOSFET to remove excess majority carrier charge.
A further object of the invention is to provide a method and structure for an SOI body-contact that requires only one additional masking level.
It is yet another object of the present invention to provide a method and structure for an SOI body-contact that consumes no additional real estate on a substrate.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.